title: Intraoperative and anatomical descriptions of intracranial connections between the glossopharyngeal and vagus nerves: clinical implications.
abstract: OBJECTIVE
  Knowledge of the variations in the nerves of the posterior cranial fossa may be important during skull base approaches. To the authors' knowledge, intracranial neural interconnections between the glossopharyngeal and vagus nerves have not been previously investigated.
  
  
  METHODS
  The senior author (A.C.G.) noted the presence of an intracranial interneural connection between the glossopharyngeal and vagus nerves during microvascular decompression surgery in a patient suffering from hemifacial spasm. To further investigate the approximate incidence and significance of such an interneural connection, the authors studied 40 adult human cadavers (80 sides) and prospectively evaluated 16 additional patients during microvascular procedures of the posterior cranial fossa.
  
  
  RESULTS
  In the cadavers, the incidence of intracranial neural connections between the glossopharyngeal and vagus nerves was 2.5%. The only such connection found in our series of living patients was in the patient in whom the connection was initially identified. These interconnections were more common on the left side. Based on our findings, we classified these neural connections as Types I and II. In the cadavers, the length and width of this connection were approximately 9 mm and 1 mm, respectively. Histological analysis of these connections verified their neural content.
  
  
  CONCLUSIONS
  Although these connections are rare and the significance is unknown, knowledge of them may prove useful to surgeons who operate in the posterior fossa region so that they may avoid inadvertent traction or transection of these interconnections. Additionally, such connections might be considered in patients with recalcitrant neuralgia after microvascular decompression and rhizotomy of the glossopharyngeal nerve.
authors.affiliation: Pediatric Neurosurgery, Children's Hospital, Birmingham, Alabama, USA.
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
authors.forename: Martin M
authors.initials: MM
authors.lastname: Mortazavi
authors.forename: Marios
authors.initials: M
authors.lastname: Loukas
authors.forename: Mohammadali M
authors.initials: MM
authors.lastname: Shoja
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Cohen-Gadol
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D003388:Cranial Fossa, Posterior / Q000033:anatomy & histology* / Q000601:surgery; D005260:Female; D005930:Glossopharyngeal Nerve / Q000033:anatomy & histology*; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D014630:Vagus Nerve / Q000033:anatomy & histology*